Secondary batteries which are highly applicable to various products and exhibit superior electrical properties such as high energy density, etc. are commonly used not only in portable devices but also in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electrical power sources. The secondary battery is drawing attentions as a new energy source for enhancing environment friendliness and energy efficiency in that the use of fossil fuels can be reduced greatly and no byproduct is generated during energy consumption.
Secondary batteries widely used at the preset include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries and the like. An operating voltage of the unit secondary battery cell, namely a unit battery cell, is about 2.5V to 4.2V. Therefore, if a higher output voltage is required, a plurality of battery cells may be connected in series to configure a battery pack. In addition, depending on the charge/discharge capacity required for the battery pack, a plurality of battery cells may be connected in parallel to configure a battery pack. Thus, the number of battery cells included in the battery pack may be variously set according to the required output voltage or the demanded charge/discharge capacity.
Meanwhile, when a plurality of battery cells are connected in series or in parallel to configure a battery pack, it is common to configure a battery module composed of at least one battery cell first, and then configure a battery pack by using at least one battery module and adding other components.
Here, the battery module includes a module case in which battery cells and various electrical parts are packaged, and a module connector connected to an external connector for electrical connection with an external device outside the module case. The external connector may be, for example, a connector for electrically connecting a plurality of battery modules.
However, in the conventional battery module, the module connector connected to the external connector is not sealed with the module case, but a wire or the like is partially exposed out of the module case, and thus a predetermined gap is created between the wire and the module case.
Accordingly, in the conventional battery module, impurities such as cooling water, fluids and dust may be introduced into the module case due to an external impact, thereby causing defects in the battery cells and various electric parts inside the module case.
Therefore, it is required to find a way to prevent the penetration of impurities into the module case near the module connector mounted at the module case.